Atmospheric de-aliasing is one of the most important background models for recovering Earth's temporal gravity field from gravity satellite missions.To meet the needs of China's gravimetric satellite platform,...Atmospheric de-aliasing is one of the most important background models for recovering Earth's temporal gravity field from gravity satellite missions.To meet the needs of China's gravimetric satellite platform,an independent atmospheric dealiasing model that relies on Chinese meteorological data needs to be developed.The release of CRA-40,as the firstgeneration Chinese atmospheric reanalysis,provides the opportunity.This study proposes a revised modeling method to calibrate CRA-40 and develops a new atmospheric de-aliasing model(HUST-CRA,2002-20).Intensive assessments are made between HUST-CRA and the latest official de-aliasing product of the international gravity satellite mission.The tidal components of the two products demonstrate high consistency,e.g.,the spatial correlation for the major tide S_1 is 0.96.The non-tidal components of the two products are also equivalent:(1)the temporal correlation of low-degree terms is higher than 0.97,except for the term of S22(0.93);(2)the spectral correlation of degree geoid height up to degree/order 100 is as high as 0.99;(3)the confidence interval of the spatial correlation(2002-20)is[0.971,0.995]at a confidence level of 95%;and(4)the difference in KBRR(K-band range rate)residuals is less than 0.08μm s^(-1),the difference in the derived temporal gravity field is less than 0.32 mm in terms of geoid height,and both are apparently beyond the ability of the current gravity satellite mission.This confirms that CRA-40 is of high quality and that the derived de-aliasing product,HUST-CRA,is accurate enough to be used in both Chinese and international gravity satellite missions.展开更多
A general matrix formula is proposed for signal spectral aliasing of various or mutual resolution, the concept of spectral aliasing matrix is introduced, and some general spectral methods for spatial resolution improv...A general matrix formula is proposed for signal spectral aliasing of various or mutual resolution, the concept of spectral aliasing matrix is introduced, and some general spectral methods for spatial resolution improvement from multiframes of undersampled digital images are discussed. A simplified iterative method of parallel row-action projection for spectral de-aliasing is also given. The method can be applied to multiframe images with various spatial resolution,relative displacement, dissimilar point spread function, different image radiance, and additive random noise. Some experiments with a resolution test pattern and an image of vertical fin performed the convergence and the effectiveness of the algorithms.展开更多
基金financial support from the National Natural Science Foundation of China(Grant Nos.42274112 and 41804016)supported by Danmarks Frie Forskningsfond[https://doi.org/10.46540/2035-00247B]through the DANSk-LSM project and HPC Platform of Huazhong University of Science and Technology。
文摘Atmospheric de-aliasing is one of the most important background models for recovering Earth's temporal gravity field from gravity satellite missions.To meet the needs of China's gravimetric satellite platform,an independent atmospheric dealiasing model that relies on Chinese meteorological data needs to be developed.The release of CRA-40,as the firstgeneration Chinese atmospheric reanalysis,provides the opportunity.This study proposes a revised modeling method to calibrate CRA-40 and develops a new atmospheric de-aliasing model(HUST-CRA,2002-20).Intensive assessments are made between HUST-CRA and the latest official de-aliasing product of the international gravity satellite mission.The tidal components of the two products demonstrate high consistency,e.g.,the spatial correlation for the major tide S_1 is 0.96.The non-tidal components of the two products are also equivalent:(1)the temporal correlation of low-degree terms is higher than 0.97,except for the term of S22(0.93);(2)the spectral correlation of degree geoid height up to degree/order 100 is as high as 0.99;(3)the confidence interval of the spatial correlation(2002-20)is[0.971,0.995]at a confidence level of 95%;and(4)the difference in KBRR(K-band range rate)residuals is less than 0.08μm s^(-1),the difference in the derived temporal gravity field is less than 0.32 mm in terms of geoid height,and both are apparently beyond the ability of the current gravity satellite mission.This confirms that CRA-40 is of high quality and that the derived de-aliasing product,HUST-CRA,is accurate enough to be used in both Chinese and international gravity satellite missions.
文摘A general matrix formula is proposed for signal spectral aliasing of various or mutual resolution, the concept of spectral aliasing matrix is introduced, and some general spectral methods for spatial resolution improvement from multiframes of undersampled digital images are discussed. A simplified iterative method of parallel row-action projection for spectral de-aliasing is also given. The method can be applied to multiframe images with various spatial resolution,relative displacement, dissimilar point spread function, different image radiance, and additive random noise. Some experiments with a resolution test pattern and an image of vertical fin performed the convergence and the effectiveness of the algorithms.
